1 /* Handle exceptional things in C++.
2 Copyright (C) 1989, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999,
3 2000, 2001, 2002, 2003, 2004, 2005, 2007 Free Software Foundation, Inc.
4 Contributed by Michael Tiemann <tiemann@cygnus.com>
5 Rewritten by Mike Stump <mrs@cygnus.com>, based upon an
6 initial re-implementation courtesy Tad Hunt.
8 This file is part of GCC.
10 GCC is free software; you can redistribute it and/or modify
11 it under the terms of the GNU General Public License as published by
12 the Free Software Foundation; either version 3, or (at your option)
15 GCC is distributed in the hope that it will be useful,
16 but WITHOUT ANY WARRANTY; without even the implied warranty of
17 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
18 GNU General Public License for more details.
20 You should have received a copy of the GNU General Public License
21 along with GCC; see the file COPYING3. If not see
22 <http://www.gnu.org/licenses/>. */
27 #include "coretypes.h"
38 #include "tree-inline.h"
39 #include "tree-iterator.h"
42 static void push_eh_cleanup (tree
);
43 static tree
prepare_eh_type (tree
);
44 static tree
build_eh_type_type (tree
);
45 static tree
do_begin_catch (void);
46 static int dtor_nothrow (tree
);
47 static tree
do_end_catch (tree
);
48 static bool decl_is_java_type (tree decl
, int err
);
49 static void initialize_handler_parm (tree
, tree
);
50 static tree
do_allocate_exception (tree
);
51 static tree
wrap_cleanups_r (tree
*, int *, void *);
52 static int complete_ptr_ref_or_void_ptr_p (tree
, tree
);
53 static bool is_admissible_throw_operand (tree
);
54 static int can_convert_eh (tree
, tree
);
55 static tree
cp_protect_cleanup_actions (void);
57 /* Sets up all the global eh stuff that needs to be initialized at the
58 start of compilation. */
61 init_exception_processing (void)
65 /* void std::terminate (); */
66 push_namespace (std_identifier
);
67 tmp
= build_function_type (void_type_node
, void_list_node
);
68 terminate_node
= build_cp_library_fn_ptr ("terminate", tmp
);
69 TREE_THIS_VOLATILE (terminate_node
) = 1;
70 TREE_NOTHROW (terminate_node
) = 1;
73 /* void __cxa_call_unexpected(void *); */
74 tmp
= tree_cons (NULL_TREE
, ptr_type_node
, void_list_node
);
75 tmp
= build_function_type (void_type_node
, tmp
);
77 = push_throw_library_fn (get_identifier ("__cxa_call_unexpected"), tmp
);
79 eh_personality_libfunc
= init_one_libfunc (USING_SJLJ_EXCEPTIONS
80 ? "__gxx_personality_sj0"
81 : "__gxx_personality_v0");
82 if (targetm
.arm_eabi_unwinder
)
83 unwind_resume_libfunc
= init_one_libfunc ("__cxa_end_cleanup");
85 default_init_unwind_resume_libfunc ();
87 lang_eh_runtime_type
= build_eh_type_type
;
88 lang_protect_cleanup_actions
= &cp_protect_cleanup_actions
;
91 /* Returns an expression to be executed if an unhandled exception is
92 propagated out of a cleanup region. */
95 cp_protect_cleanup_actions (void)
99 When the destruction of an object during stack unwinding exits
100 using an exception ... void terminate(); is called. */
101 return build_call_n (terminate_node
, 0);
105 prepare_eh_type (tree type
)
107 if (type
== NULL_TREE
)
109 if (type
== error_mark_node
)
110 return error_mark_node
;
112 /* peel back references, so they match. */
113 type
= non_reference (type
);
115 /* Peel off cv qualifiers. */
116 type
= TYPE_MAIN_VARIANT (type
);
121 /* Return the type info for TYPE as used by EH machinery. */
123 eh_type_info (tree type
)
127 if (type
== NULL_TREE
|| type
== error_mark_node
)
130 if (decl_is_java_type (type
, 0))
131 exp
= build_java_class_ref (TREE_TYPE (type
));
133 exp
= get_tinfo_decl (type
);
138 /* Build the address of a typeinfo decl for use in the runtime
139 matching field of the exception model. */
142 build_eh_type_type (tree type
)
144 tree exp
= eh_type_info (type
);
151 return convert (ptr_type_node
, build_address (exp
));
157 return build0 (EXC_PTR_EXPR
, ptr_type_node
);
160 /* Build up a call to __cxa_get_exception_ptr so that we can build a
161 copy constructor for the thrown object. */
164 do_get_exception_ptr (void)
168 fn
= get_identifier ("__cxa_get_exception_ptr");
169 if (!get_global_value_if_present (fn
, &fn
))
171 /* Declare void* __cxa_get_exception_ptr (void *). */
172 tree tmp
= tree_cons (NULL_TREE
, ptr_type_node
, void_list_node
);
173 fn
= push_library_fn (fn
, build_function_type (ptr_type_node
, tmp
));
176 return build_function_call (fn
, tree_cons (NULL_TREE
, build_exc_ptr (),
180 /* Build up a call to __cxa_begin_catch, to tell the runtime that the
181 exception has been handled. */
184 do_begin_catch (void)
188 fn
= get_identifier ("__cxa_begin_catch");
189 if (!get_global_value_if_present (fn
, &fn
))
191 /* Declare void* __cxa_begin_catch (void *). */
192 tree tmp
= tree_cons (NULL_TREE
, ptr_type_node
, void_list_node
);
193 fn
= push_library_fn (fn
, build_function_type (ptr_type_node
, tmp
));
196 return build_function_call (fn
, tree_cons (NULL_TREE
, build_exc_ptr (),
200 /* Returns nonzero if cleaning up an exception of type TYPE (which can be
201 NULL_TREE for a ... handler) will not throw an exception. */
204 dtor_nothrow (tree type
)
206 if (type
== NULL_TREE
)
209 if (!CLASS_TYPE_P (type
))
212 if (CLASSTYPE_LAZY_DESTRUCTOR (type
))
213 lazily_declare_fn (sfk_destructor
, type
);
215 return TREE_NOTHROW (CLASSTYPE_DESTRUCTORS (type
));
218 /* Build up a call to __cxa_end_catch, to destroy the exception object
219 for the current catch block if no others are currently using it. */
222 do_end_catch (tree type
)
226 fn
= get_identifier ("__cxa_end_catch");
227 if (!get_global_value_if_present (fn
, &fn
))
229 /* Declare void __cxa_end_catch (). */
230 fn
= push_void_library_fn (fn
, void_list_node
);
231 /* This can throw if the destructor for the exception throws. */
232 TREE_NOTHROW (fn
) = 0;
235 cleanup
= build_function_call (fn
, NULL_TREE
);
236 TREE_NOTHROW (cleanup
) = dtor_nothrow (type
);
241 /* This routine creates the cleanup for the current exception. */
244 push_eh_cleanup (tree type
)
246 finish_decl_cleanup (NULL_TREE
, do_end_catch (type
));
249 /* Return nonzero value if DECL is a Java type suitable for catch or
253 decl_is_java_type (tree decl
, int err
)
255 bool r
= (TREE_CODE (decl
) == POINTER_TYPE
256 && TREE_CODE (TREE_TYPE (decl
)) == RECORD_TYPE
257 && TYPE_FOR_JAVA (TREE_TYPE (decl
)));
261 if (TREE_CODE (decl
) == REFERENCE_TYPE
262 && TREE_CODE (TREE_TYPE (decl
)) == RECORD_TYPE
263 && TYPE_FOR_JAVA (TREE_TYPE (decl
)))
265 /* Can't throw a reference. */
266 error ("type %qT is disallowed in Java %<throw%> or %<catch%>",
273 = IDENTIFIER_GLOBAL_VALUE (get_identifier ("jthrowable"));
275 if (jthrow_node
== NULL_TREE
)
277 ("call to Java %<catch%> or %<throw%> with %<jthrowable%> undefined");
279 jthrow_node
= TREE_TYPE (TREE_TYPE (jthrow_node
));
281 if (! DERIVED_FROM_P (jthrow_node
, TREE_TYPE (decl
)))
283 /* Thrown object must be a Throwable. */
284 error ("type %qT is not derived from %<java::lang::Throwable%>",
293 /* Select the personality routine to be used for exception handling,
294 or issue an error if we need two different ones in the same
296 ??? At present eh_personality_libfunc is set to
297 __gxx_personality_(sj|v)0 in init_exception_processing - should it
298 be done here instead? */
300 choose_personality_routine (enum languages lang
)
315 if (lang
!= lang_cplusplus
)
320 if (lang
!= lang_java
)
325 ; /* Proceed to language selection. */
336 eh_personality_libfunc
= init_one_libfunc (USING_SJLJ_EXCEPTIONS
337 ? "__gcj_personality_sj0"
338 : "__gcj_personality_v0");
347 error ("mixing C++ and Java catches in a single translation unit");
351 /* Initialize the catch parameter DECL. */
354 initialize_handler_parm (tree decl
, tree exp
)
359 /* Make sure we mark the catch param as used, otherwise we'll get a
360 warning about an unused ((anonymous)). */
361 TREE_USED (decl
) = 1;
363 /* Figure out the type that the initializer is. Pointers are returned
364 adjusted by value from __cxa_begin_catch. Others are returned by
366 init_type
= TREE_TYPE (decl
);
367 if (!POINTER_TYPE_P (init_type
))
368 init_type
= build_reference_type (init_type
);
370 choose_personality_routine (decl_is_java_type (init_type
, 0)
371 ? lang_java
: lang_cplusplus
);
373 /* Since pointers are passed by value, initialize a reference to
374 pointer catch parm with the address of the temporary. */
375 if (TREE_CODE (init_type
) == REFERENCE_TYPE
376 && TYPE_PTR_P (TREE_TYPE (init_type
)))
377 exp
= build_unary_op (ADDR_EXPR
, exp
, 1);
379 exp
= ocp_convert (init_type
, exp
, CONV_IMPLICIT
|CONV_FORCE_TEMP
, 0);
381 init
= convert_from_reference (exp
);
383 /* If the constructor for the catch parm exits via an exception, we
384 must call terminate. See eh23.C. */
385 if (TYPE_NEEDS_CONSTRUCTING (TREE_TYPE (decl
)))
387 /* Generate the copy constructor call directly so we can wrap it.
388 See also expand_default_init. */
389 init
= ocp_convert (TREE_TYPE (decl
), init
,
390 CONV_IMPLICIT
|CONV_FORCE_TEMP
, 0);
391 init
= build1 (MUST_NOT_THROW_EXPR
, TREE_TYPE (init
), init
);
394 decl
= pushdecl (decl
);
396 start_decl_1 (decl
, true);
397 cp_finish_decl (decl
, init
, /*init_const_expr_p=*/false, NULL_TREE
,
398 LOOKUP_ONLYCONVERTING
|DIRECT_BIND
);
401 /* Call this to start a catch block. DECL is the catch parameter. */
404 expand_start_catch_block (tree decl
)
412 /* Make sure this declaration is reasonable. */
413 if (decl
&& !complete_ptr_ref_or_void_ptr_p (TREE_TYPE (decl
), NULL_TREE
))
414 decl
= error_mark_node
;
417 type
= prepare_eh_type (TREE_TYPE (decl
));
421 if (decl
&& decl_is_java_type (type
, 1))
423 /* Java only passes object via pointer and doesn't require
424 adjusting. The java object is immediately before the
425 generic exception header. */
426 exp
= build_exc_ptr ();
427 exp
= build1 (NOP_EXPR
, build_pointer_type (type
), exp
);
428 exp
= build2 (POINTER_PLUS_EXPR
, TREE_TYPE (exp
), exp
,
429 fold_build1 (NEGATE_EXPR
, sizetype
,
430 TYPE_SIZE_UNIT (TREE_TYPE (exp
))));
431 exp
= build_indirect_ref (exp
, NULL
);
432 initialize_handler_parm (decl
, exp
);
436 /* Call __cxa_end_catch at the end of processing the exception. */
437 push_eh_cleanup (type
);
439 /* If there's no decl at all, then all we need to do is make sure
440 to tell the runtime that we've begun handling the exception. */
441 if (decl
== NULL
|| decl
== error_mark_node
)
442 finish_expr_stmt (do_begin_catch ());
444 /* If the C++ object needs constructing, we need to do that before
445 calling __cxa_begin_catch, so that std::uncaught_exception gets
446 the right value during the copy constructor. */
447 else if (flag_use_cxa_get_exception_ptr
448 && TYPE_NEEDS_CONSTRUCTING (TREE_TYPE (decl
)))
450 exp
= do_get_exception_ptr ();
451 initialize_handler_parm (decl
, exp
);
452 finish_expr_stmt (do_begin_catch ());
455 /* Otherwise the type uses a bitwise copy, and we don't have to worry
456 about the value of std::uncaught_exception and therefore can do the
457 copy with the return value of __cxa_end_catch instead. */
460 tree init
= do_begin_catch ();
461 tree init_type
= type
;
463 /* Pointers are passed by values, everything else by reference. */
464 if (!TYPE_PTR_P (type
))
465 init_type
= build_pointer_type (type
);
466 if (init_type
!= TREE_TYPE (init
))
467 init
= build1 (NOP_EXPR
, init_type
, init
);
468 exp
= create_temporary_var (init_type
);
469 DECL_REGISTER (exp
) = 1;
470 cp_finish_decl (exp
, init
, /*init_const_expr=*/false,
471 NULL_TREE
, LOOKUP_ONLYCONVERTING
);
472 initialize_handler_parm (decl
, exp
);
479 /* Call this to end a catch block. Its responsible for emitting the
480 code to handle jumping back to the correct place, and for emitting
481 the label to jump to if this catch block didn't match. */
484 expand_end_catch_block (void)
489 /* The exception being handled is rethrown if control reaches the end of
490 a handler of the function-try-block of a constructor or destructor. */
491 if (in_function_try_handler
492 && (DECL_CONSTRUCTOR_P (current_function_decl
)
493 || DECL_DESTRUCTOR_P (current_function_decl
)))
494 finish_expr_stmt (build_throw (NULL_TREE
));
498 begin_eh_spec_block (void)
500 tree r
= build_stmt (EH_SPEC_BLOCK
, NULL_TREE
, NULL_TREE
);
502 EH_SPEC_STMTS (r
) = push_stmt_list ();
507 finish_eh_spec_block (tree raw_raises
, tree eh_spec_block
)
511 EH_SPEC_STMTS (eh_spec_block
) = pop_stmt_list (EH_SPEC_STMTS (eh_spec_block
));
513 /* Strip cv quals, etc, from the specification types. */
514 for (raises
= NULL_TREE
;
515 raw_raises
&& TREE_VALUE (raw_raises
);
516 raw_raises
= TREE_CHAIN (raw_raises
))
518 tree type
= prepare_eh_type (TREE_VALUE (raw_raises
));
519 tree tinfo
= eh_type_info (type
);
522 raises
= tree_cons (NULL_TREE
, type
, raises
);
525 EH_SPEC_RAISES (eh_spec_block
) = raises
;
528 /* Return a pointer to a buffer for an exception object of type TYPE. */
531 do_allocate_exception (tree type
)
535 fn
= get_identifier ("__cxa_allocate_exception");
536 if (!get_global_value_if_present (fn
, &fn
))
538 /* Declare void *__cxa_allocate_exception(size_t). */
539 tree tmp
= tree_cons (NULL_TREE
, size_type_node
, void_list_node
);
540 fn
= push_library_fn (fn
, build_function_type (ptr_type_node
, tmp
));
543 return build_function_call (fn
, tree_cons (NULL_TREE
, size_in_bytes (type
),
547 /* Call __cxa_free_exception from a cleanup. This is never invoked
548 directly, but see the comment for stabilize_throw_expr. */
551 do_free_exception (tree ptr
)
555 fn
= get_identifier ("__cxa_free_exception");
556 if (!get_global_value_if_present (fn
, &fn
))
558 /* Declare void __cxa_free_exception (void *). */
559 fn
= push_void_library_fn (fn
, tree_cons (NULL_TREE
, ptr_type_node
,
563 return build_function_call (fn
, tree_cons (NULL_TREE
, ptr
, NULL_TREE
));
566 /* Wrap all cleanups for TARGET_EXPRs in MUST_NOT_THROW_EXPR.
567 Called from build_throw via walk_tree_without_duplicates. */
570 wrap_cleanups_r (tree
*tp
, int *walk_subtrees ATTRIBUTE_UNUSED
,
571 void *data ATTRIBUTE_UNUSED
)
576 /* Don't walk into types. */
582 if (TREE_CODE (exp
) != TARGET_EXPR
)
585 cleanup
= TARGET_EXPR_CLEANUP (exp
);
588 cleanup
= build1 (MUST_NOT_THROW_EXPR
, void_type_node
, cleanup
);
589 TARGET_EXPR_CLEANUP (exp
) = cleanup
;
592 /* Keep iterating. */
596 /* Build a throw expression. */
599 build_throw (tree exp
)
603 if (exp
== error_mark_node
)
606 if (processing_template_decl
)
609 current_function_returns_abnormally
= 1;
610 return build_min (THROW_EXPR
, void_type_node
, exp
);
613 if (exp
== null_node
)
614 warning (0, "throwing NULL, which has integral, not pointer type");
616 if (exp
!= NULL_TREE
)
618 if (!is_admissible_throw_operand (exp
))
619 return error_mark_node
;
623 return error_mark_node
;
625 if (exp
&& decl_is_java_type (TREE_TYPE (exp
), 1))
627 tree fn
= get_identifier ("_Jv_Throw");
628 if (!get_global_value_if_present (fn
, &fn
))
630 /* Declare void _Jv_Throw (void *). */
631 tree tmp
= tree_cons (NULL_TREE
, ptr_type_node
, void_list_node
);
632 tmp
= build_function_type (ptr_type_node
, tmp
);
633 fn
= push_throw_library_fn (fn
, tmp
);
635 else if (really_overloaded_fn (fn
))
637 error ("%qD should never be overloaded", fn
);
638 return error_mark_node
;
640 fn
= OVL_CURRENT (fn
);
641 exp
= build_function_call (fn
, tree_cons (NULL_TREE
, exp
, NULL_TREE
));
650 tree temp_expr
, allocate_expr
;
653 /* The CLEANUP_TYPE is the internal type of a destructor. */
656 tmp
= void_list_node
;
657 tmp
= tree_cons (NULL_TREE
, ptr_type_node
, tmp
);
658 tmp
= build_function_type (void_type_node
, tmp
);
659 cleanup_type
= build_pointer_type (tmp
);
662 fn
= get_identifier ("__cxa_throw");
663 if (!get_global_value_if_present (fn
, &fn
))
665 /* Declare void __cxa_throw (void*, void*, void (*)(void*)). */
666 /* ??? Second argument is supposed to be "std::type_info*". */
667 tmp
= void_list_node
;
668 tmp
= tree_cons (NULL_TREE
, cleanup_type
, tmp
);
669 tmp
= tree_cons (NULL_TREE
, ptr_type_node
, tmp
);
670 tmp
= tree_cons (NULL_TREE
, ptr_type_node
, tmp
);
671 tmp
= build_function_type (void_type_node
, tmp
);
672 fn
= push_throw_library_fn (fn
, tmp
);
677 A throw-expression initializes a temporary object, the type
678 of which is determined by removing any top-level
679 cv-qualifiers from the static type of the operand of throw
680 and adjusting the type from "array of T" or "function return
681 T" to "pointer to T" or "pointer to function returning T"
683 temp_type
= is_bitfield_expr_with_lowered_type (exp
);
685 temp_type
= type_decays_to (TREE_TYPE (exp
));
687 /* OK, this is kind of wacky. The standard says that we call
688 terminate when the exception handling mechanism, after
689 completing evaluation of the expression to be thrown but
690 before the exception is caught (_except.throw_), calls a
691 user function that exits via an uncaught exception.
693 So we have to protect the actual initialization of the
694 exception object with terminate(), but evaluate the
695 expression first. Since there could be temps in the
696 expression, we need to handle that, too. We also expand
697 the call to __cxa_allocate_exception first (which doesn't
698 matter, since it can't throw). */
700 /* Allocate the space for the exception. */
701 allocate_expr
= do_allocate_exception (temp_type
);
702 allocate_expr
= get_target_expr (allocate_expr
);
703 ptr
= TARGET_EXPR_SLOT (allocate_expr
);
704 object
= build_nop (build_pointer_type (temp_type
), ptr
);
705 object
= build_indirect_ref (object
, NULL
);
707 elided
= (TREE_CODE (exp
) == TARGET_EXPR
);
709 /* And initialize the exception object. */
710 if (CLASS_TYPE_P (temp_type
))
712 int flags
= LOOKUP_NORMAL
| LOOKUP_ONLYCONVERTING
;
714 /* Under C++0x [12.8/16 class.copy], a thrown lvalue is sometimes
715 treated as an rvalue for the purposes of overload resolution
716 to favor move constructors over copy constructors. */
717 if (/* Must be a local, automatic variable. */
718 TREE_CODE (exp
) == VAR_DECL
719 && DECL_CONTEXT (exp
) == current_function_decl
720 && ! TREE_STATIC (exp
)
721 /* The variable must not have the `volatile' qualifier. */
722 && !(cp_type_quals (TREE_TYPE (exp
)) & TYPE_QUAL_VOLATILE
))
723 flags
= flags
| LOOKUP_PREFER_RVALUE
;
725 /* Call the copy constructor. */
726 exp
= (build_special_member_call
727 (object
, complete_ctor_identifier
,
728 build_tree_list (NULL_TREE
, exp
),
731 if (exp
== error_mark_node
)
733 error (" in thrown expression");
734 return error_mark_node
;
738 exp
= build2 (INIT_EXPR
, temp_type
, object
,
739 decay_conversion (exp
));
741 /* Pre-evaluate the thrown expression first, since if we allocated
742 the space first we would have to deal with cleaning it up if
743 evaluating this expression throws.
745 The case where EXP the initializer is a cast or a function
746 returning a class is a bit of a grey area in the standard; it's
747 unclear whether or not it should be allowed to throw. We used to
748 say no, as that allowed us to optimize this case without worrying
749 about deallocating the exception object if it does. But that
750 conflicted with expectations (PR 13944) and the EDG compiler; now
751 we wrap the initialization in a TRY_CATCH_EXPR to call
752 do_free_exception rather than in a MUST_NOT_THROW_EXPR, for this
755 BUT: Issue 475 may do away with this inconsistency by removing the
756 terminate() in this situation.
758 Note that we don't check the return value from stabilize_init
759 because it will only return false in cases where elided is true,
760 and therefore we don't need to work around the failure to
762 temp_expr
= NULL_TREE
;
763 stabilize_init (exp
, &temp_expr
);
765 /* Wrap the initialization in a CLEANUP_POINT_EXPR so that cleanups
766 for temporaries within the initialization are run before the one
767 for the exception object, preserving LIFO order. */
768 exp
= build1 (CLEANUP_POINT_EXPR
, void_type_node
, exp
);
771 exp
= build2 (TRY_CATCH_EXPR
, void_type_node
, exp
,
772 do_free_exception (ptr
));
774 exp
= build1 (MUST_NOT_THROW_EXPR
, void_type_node
, exp
);
776 /* Prepend the allocation. */
777 exp
= build2 (COMPOUND_EXPR
, TREE_TYPE (exp
), allocate_expr
, exp
);
780 /* Prepend the calculation of the throw expression. Also, force
781 any cleanups from the expression to be evaluated here so that
782 we don't have to do them during unwinding. But first wrap
783 them in MUST_NOT_THROW_EXPR, since they are run after the
784 exception object is initialized. */
785 cp_walk_tree_without_duplicates (&temp_expr
, wrap_cleanups_r
, 0);
786 exp
= build2 (COMPOUND_EXPR
, TREE_TYPE (exp
), temp_expr
, exp
);
787 exp
= build1 (CLEANUP_POINT_EXPR
, TREE_TYPE (exp
), exp
);
790 throw_type
= build_eh_type_type (prepare_eh_type (TREE_TYPE (object
)));
792 if (TYPE_HAS_NONTRIVIAL_DESTRUCTOR (TREE_TYPE (object
)))
794 cleanup
= lookup_fnfields (TYPE_BINFO (TREE_TYPE (object
)),
795 complete_dtor_identifier
, 0);
796 cleanup
= BASELINK_FUNCTIONS (cleanup
);
798 cxx_mark_addressable (cleanup
);
799 /* Pretend it's a normal function. */
800 cleanup
= build1 (ADDR_EXPR
, cleanup_type
, cleanup
);
803 cleanup
= build_int_cst (cleanup_type
, 0);
805 tmp
= tree_cons (NULL_TREE
, cleanup
, NULL_TREE
);
806 tmp
= tree_cons (NULL_TREE
, throw_type
, tmp
);
807 tmp
= tree_cons (NULL_TREE
, ptr
, tmp
);
808 /* ??? Indicate that this function call throws throw_type. */
809 tmp
= build_function_call (fn
, tmp
);
811 /* Tack on the initialization stuff. */
812 exp
= build2 (COMPOUND_EXPR
, TREE_TYPE (tmp
), exp
, tmp
);
816 /* Rethrow current exception. */
818 tree fn
= get_identifier ("__cxa_rethrow");
819 if (!get_global_value_if_present (fn
, &fn
))
821 /* Declare void __cxa_rethrow (void). */
822 fn
= push_throw_library_fn
823 (fn
, build_function_type (void_type_node
, void_list_node
));
826 /* ??? Indicate that this function call allows exceptions of the type
827 of the enclosing catch block (if known). */
828 exp
= build_function_call (fn
, NULL_TREE
);
831 exp
= build1 (THROW_EXPR
, void_type_node
, exp
);
836 /* Make sure TYPE is complete, pointer to complete, reference to
837 complete, or pointer to cv void. Issue diagnostic on failure.
838 Return the zero on failure and nonzero on success. FROM can be
839 the expr or decl from whence TYPE came, if available. */
842 complete_ptr_ref_or_void_ptr_p (tree type
, tree from
)
846 /* Check complete. */
847 type
= complete_type_or_else (type
, from
);
851 /* Or a pointer or ref to one, or cv void *. */
852 is_ptr
= TREE_CODE (type
) == POINTER_TYPE
;
853 if (is_ptr
|| TREE_CODE (type
) == REFERENCE_TYPE
)
855 tree core
= TREE_TYPE (type
);
857 if (is_ptr
&& VOID_TYPE_P (core
))
859 else if (!complete_type_or_else (core
, from
))
865 /* Return truth-value if EXPRESSION is admissible in throw-expression,
866 i.e. if it is not of incomplete type or a pointer/reference to such
867 a type or of an abstract class type. */
870 is_admissible_throw_operand (tree expr
)
872 tree type
= TREE_TYPE (expr
);
874 /* 15.1/4 [...] The type of the throw-expression shall not be an
875 incomplete type, or a pointer or a reference to an incomplete
876 type, other than void*, const void*, volatile void*, or
877 const volatile void*. Except for these restriction and the
878 restrictions on type matching mentioned in 15.3, the operand
879 of throw is treated exactly as a function argument in a call
880 (5.2.2) or the operand of a return statement. */
881 if (!complete_ptr_ref_or_void_ptr_p (type
, expr
))
884 /* 10.4/3 An abstract class shall not be used as a parameter type,
885 as a function return type or as type of an explicit
887 else if (CLASS_TYPE_P (type
) && CLASSTYPE_PURE_VIRTUALS (type
))
889 error ("expression %qE of abstract class type %qT cannot "
890 "be used in throw-expression", expr
, type
);
897 /* Returns nonzero if FN is a declaration of a standard C library
898 function which is known not to throw.
900 [lib.res.on.exception.handling]: None of the functions from the
901 Standard C library shall report an error by throwing an
902 exception, unless it calls a program-supplied function that
903 throws an exception. */
908 nothrow_libfn_p (const_tree fn
)
913 && DECL_EXTERNAL (fn
)
914 && DECL_NAMESPACE_SCOPE_P (fn
)
915 && DECL_EXTERN_C_P (fn
))
918 /* Can't be a C library function. */
921 /* Being a C library function, DECL_ASSEMBLER_NAME == DECL_NAME
922 unless the system headers are playing rename tricks, and if
923 they are, we don't want to be confused by them. */
925 return !!libc_name_p (IDENTIFIER_POINTER (id
), IDENTIFIER_LENGTH (id
));
928 /* Returns nonzero if an exception of type FROM will be caught by a
929 handler for type TO, as per [except.handle]. */
932 can_convert_eh (tree to
, tree from
)
934 to
= non_reference (to
);
935 from
= non_reference (from
);
937 if (TREE_CODE (to
) == POINTER_TYPE
&& TREE_CODE (from
) == POINTER_TYPE
)
940 from
= TREE_TYPE (from
);
942 if (! at_least_as_qualified_p (to
, from
))
945 if (TREE_CODE (to
) == VOID_TYPE
)
948 /* Else fall through. */
951 if (CLASS_TYPE_P (to
) && CLASS_TYPE_P (from
)
952 && PUBLICLY_UNIQUELY_DERIVED_P (to
, from
))
958 /* Check whether any of the handlers in I are shadowed by another handler
959 accepting TYPE. Note that the shadowing may not be complete; even if
960 an exception of type B would be caught by a handler for A, there could
961 be a derived class C for which A is an ambiguous base but B is not, so
962 the handler for B would catch an exception of type C. */
965 check_handlers_1 (tree master
, tree_stmt_iterator i
)
967 tree type
= TREE_TYPE (master
);
969 for (; !tsi_end_p (i
); tsi_next (&i
))
971 tree handler
= tsi_stmt (i
);
972 if (TREE_TYPE (handler
) && can_convert_eh (type
, TREE_TYPE (handler
)))
974 warning (0, "%Hexception of type %qT will be caught",
975 EXPR_LOCUS (handler
), TREE_TYPE (handler
));
976 warning (0, "%H by earlier handler for %qT",
977 EXPR_LOCUS (master
), type
);
983 /* Given a STATEMENT_LIST of HANDLERs, make sure that they're OK. */
986 check_handlers (tree handlers
)
988 tree_stmt_iterator i
;
990 /* If we don't have a STATEMENT_LIST, then we've just got one
991 handler, and thus nothing to warn about. */
992 if (TREE_CODE (handlers
) != STATEMENT_LIST
)
995 i
= tsi_start (handlers
);
999 tree handler
= tsi_stmt (i
);
1002 /* No more handlers; nothing to shadow. */
1005 if (TREE_TYPE (handler
) == NULL_TREE
)
1006 pedwarn ("%H%<...%> handler must be the last handler for"
1007 " its try block", EXPR_LOCUS (handler
));
1009 check_handlers_1 (handler
, i
);